Here is the full list of all 35 Disc Room achievements.
DEFEAT THE ULTIMATE GATEKEEPER USING EVERY ABILITY
COMPLETE HARD MODE
UNCOVER THE GOLDEN MYSTERY
DIE FROM 4 DIFFERENT DISCS IN ONE LIFE
SURVIVE 20 SECONDS IN EVERY ROOM
EXPLORE ALL ???? ROOMS
DIE FROM ALL DISCS
EXPLORE ALL ROOMS
FOLLOW THE PATH
DISCOVER THE FOURTH GOLDEN ROOM
SURVIVE 10 SECONDS IN EVERY HARD ROOM
EXPLORE ALL HARD ROOMS
SURVIVE 20 SECONDS IN ANY HARD ROOM
QUIT TO MAIN MENU WITHIN 2 SECONDS AFTER DYING
SURVIVE 20 SECONDS IN EVERY ROOM IN ONE ZONE
SURVIVE 0 SECONDS OR LESS
FACE THE GOLDEN CARCASS
HOLD DOWN FFW FOR 10 SECONDS STRAIGHT
FEED ???? 4 ????
UNLOCK ALL 6 ABILITIES
DISCOVER THE THIRD GOLDEN ROOM
START HARD MODE
DEFEAT THE ULTIMATE GATEKEEPER
WALK 10K STEPS
???? THE ????
DEFEAT THE CARNIVOROUS GATEKEEPER
DEFEAT THE PHANTOM GATEKEEPER
DISCOVER THE SECOND GOLDEN ROOM
DIE FROM ALL DISCS IN ONE ZONE
DEFEAT AND REVIVE AN ANTIBODY
DISCOVER THE FIRST GOLDEN ROOM
DEFEAT THE OVERGROWN GATEKEEPER
END A RUN FROM THE MAP
DEFEAT THE ARMORED GATEKEEPER
SURVIVE 60 SECONDS IN ANY ROOM